Our aim is to understand the mechanisms underlying the neuroglial response to injury and the possible role of fibrous gliosis in preventing CNS regeneration. The glial fibrillary acidic protein (GFA protein), a major product of astroglial differentiation which is markedly increased in gliosed tissue will provide our major handle. The proposed studies include (in the same order as presented in the application): 1. Physiochemical characterization of GFA protein isolated by immunoaffinity chromatography. 2. Assembly and dissassembly of glial filaments. 3. Isolation of GFA and neurofilament proteins from brain filament preparations by immunoaffinity chromatography. 4. Cell proliferation and GFA expression in vivo. 5. GFA expression in vitro: Dissociated brain cells in aggregating and monolayer culture; glioma cell lines in monolayer, spinner and aggregating culture. 6. Turnover of GFA protein in vivo and in vitro. 7. Effect of different substances on fibrous gliosis of the retina and nerve regeneration after crushing the optic nerve.